#include<iostream>
using namespace std;
int main(){
	const float PI=3.14;
	float r;
	float area;
	float zhouchang;
	cout<<"Please input the radius:"<<endl;
	cin>>r;
	area=PI*r*r;
	zhouchang=2*PI*r;
	cout<<"area="<<area<<endl;
	ocut<<"zhouchang="<<zhouchang<<endl;
	}